O o q o q o q o o o q o q-o



(No Model.)

2 Sheets-Sheet 1. D. 8v J. S. HILL.

DRYING KILN.

Patented Mar. 30, 1897.

.2 Sheets-Sheet 2.

(No Model.)

DRYING KILN.

Patented Mar. 30, 1897.`

Wil

ilNTTEn STATES ATENT OEETCE.

DAVID HILL AND JAMES S. HILL, OF WASHINGTON, NORTH CAROLINA.

DRYlNG-KILN.

SPECIFICATION forming part of Letters Patent No. 579,709, dated March 30, 189'?. Application filed September 23, 1896. Serial No. 606,701. (No-model.)

To all whom t may concern:

Be it known that we,DAVID HILL and JAMES S. HILL, citizens of the United States, residing at Vashington, in the county of Beaufort and State of North Carolina, have invented certain new and useful Improvements in Drying-Kilns; and we do hereby declare the following to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains to make and use the same.

Our invention is an improvement in dryingkilns adapted particularly for drying` lumber;

and it consists in the novel features hereinafter described, reference being had to the accompanying drawings, which illustrate our invention, and it is fully disclosed in the following description and claims.

Referring to the drawings, Figure l represents a longitudinal sectional view of a kiln embodying our invention. Fig. 2 represents a horizontal sectional view of the same. Fig. 3 is a vertical transverse sectional view. Fig. 4L is a view similar to Fig. 3, showing a slightlymodilied construction. Figs. 5, 6, and 7 are views similar, respectively, to Figs. l, 2, and 3, showing a different arrangement of the heating-pipes and truck-supporting rails.

Arepresents the house or kiln proper,which is preferably of elongated rectangular shape and is provided at each end witha sliding door B and at the top with one, two, or more stacks or flues C C. We prefer to form the roof d of the kiln in the ordinary angular or curved form and to provide a ceiling a beneath it, thereby forming an air-chamber d2 between said ceiling and the roof to prevent radiation and loss'of heat from the interior, and the stacks O will therefore extend down through said air-space and having the lower ends register with the openings in the ceiling a', as shown.

Within the kiln is an inner chamber D of less width than the kiln proper and extending throughout its length, closed hermetically at its bottom and sides, but open at the top, as shown', the sides or walls d of the inner chamber being set a short distance from the outer walls of the kiln and providing airpassages between the two walls. We find it convenient in building the kiln to arrange a series of vertical supports or studs a3 along the sides of the structure and to secure the outer walls of the kiln to the outside of said studs and the walls of the inner chamber to the inner walls of the studs, thus separating the two walls and providing vertical air-spaces d4 between the studs, as shown in the drawings. The exterior wall A of the kiln is provided adjacent to its bottom with openings communicating with the vertical air-passages d4 between the walls, so that air is free to enter said openings, pass upwardly through said passages, and enter the kiln over the top of the inner or drying chamber D, as will be readily seen in Fig. 3. These openings can be conveniently provided by leaving off the bottom strip of the weather-boarding which forms the outer wall of the kiln, as will be readily understood, and as indicated at a5 in the drawings.

Vithin the drying-chamber D and adjacent to the bottom thereof we provide a horizontal steam heating-coil E, which extends the entire length of Jthe chamber and is connected with a suitable steam-supply. (Not shown.) Above the steam heating-coil we provide means for supporting the lumber to be dried. In this instance We have shown the drying-chamber provided with' suitable rails ff to support a truck F, upon which the lumber is piled and run into the kiln. Horizontal rails are shown in Figs. l to 4, but the rails may be inclined, as shown in Figs. 5 to 7, if desired. In Figs. l to 4 we have shown an ordinary horizontal steam-coil. In Figs. 5 to 7 we have shown a different form of coil, in which G represents a longitudinal central pipe extending throughout the drying-chamber in ari inclined position like the rails ff. From the central pipe G numerous lateral branch pipes g extend to the sides of the chamber, and these pipes incline upwardly from the pipe G. As a result of this construction the water of condensation will flow from all the pipes g g into the main pipe G and all the water of condensation in pipe G will now toward its lower end, where it will be conducted back to the boiler. This op- IOO chamber and steam admitted to the hea-tingcoil, the heat given ofi' from said coil produces a steady and even evaporation of the moisture from the lumber. The moisture in the form oi. vapor ascends tothe space above the lumber. A current of normal dry air will enter the kiln adjacent to its bottoln and pass up the passages a4 between the two walls, the heat from the inner wall being sufiicient to produce an upward current, and these currents of dry air are discharged directly into the space above the lumber, where they absorb the vapor in said space and pass out through the stacks, thus positively removing the moisture from the kiln as rapidly as it is removed from the lumber. The operation can be conducted with a low steam-pressure, it is even and regular, and the danger ot' cracking, warping, or bluing the lumber is avoided. A high degree of heat can be main tained in the drying-chamber with a low steam-pressure, as there are no vcurrents of cold air passing upward through the dryingehamber, as in many kilns, to lower the tem perature by extracting heat during their passage through the chamber.

In some cases Ait may be found advantageous to heat the incoming currents oi' air beiore passing them into the kiln to facilitate the removal of the vapor from the kiln without losing heat, and in Fig. 5 we have shown a construction adapted for this purpose. In this construction the kiln proper is provided with a supplemental heating-chamber H beneath the t'lrying-chz'tmber, provided with a steam heating-coil 7i., said cham berbein g directly connected with the vertical passage or passages between the d ryin g-chamber and the outer walls of the kiln, as shown. Air is admitted to the drying-chamber by means of suitable openings or ports h beneath the steam-coil h and becoming heated and expanded passes up through the vertical passages before referred to and is discharged into the space above the lumber, where it readily absorbs the aqueous vapors and carries them out through the stacks.

That we claim, and desire to secure by Letters Patent, is-

1. In a drying-kiln, the combination with a drying-chamber, sealed at its bottom and sides and having a discharge-passage communicating with the top of said chamber, of means for admitting currents of air through said drying-chamber adjacent to its top, and a heating device in said drying-chamber adjacent to its betteln, substantially as de scribed.

2. ln a dryingchamber, the combination with an inclosin g casing provided adjacent to its top with a discharge-passzztge, a dryingchamber within said casin g sealed at its bottom and sides but communicating at its upper end with said dischargepassage, vertical air-passages at each side et said drying-cham ber communicating with the outerair at their lower ends, and at their upper ends discharging into said casing abovethe top of the drying-chamber and a heater in said dryingchamber adjacent to its betteln, substantially as described. y

In a drying-kiln, the combination with a d ryin g-ch amber sealed at its bottom and sides and having a dischaige-passage communicating with the top of said chamber, of means for adn'iitting air to said chamber adjacent to its top, a heating device for said air, and a heating device located in the bottom of said dry ing-chamber, substantially as described.

a. ln a drying-kiln, the combination with a drying-chamber sealed at its bottom and sides and having adischarge-passage conimunicating with its upper end anda heater in the bottom of said chamber, of an auxiliary heatingchamber, passages extendin g from said chamber to the top of said dryi iig-chamber, a heater in said hcating-ehamber and means for admitting air to said heating-cliamber, substantially as described.

5. In a dryingkiln, the coinbiuatien with the drying-cham ber, of a heating device there- `for consisting of a central supply-pipe, inclined to discharge the water of condensation and a plurality ol lateral branch pipes connected directly with said central pipe, extending therefrom on opposite sides and inclined upwardly from said central pipe, the only openings in said pipes being at their points of com m unieation with said central pipe, substantially as described.

In testimony whereof we affix our signatures in presence of two witnesses.

DAVID HILL. JAMES S. HILL.

lVitnesses:

.losnrrr G. CHAMY, Gno. W. BAKER.

IOO 

